The invention relates to orthosis useful for the rehabilitation of injured and/or weakened joints.
Both muscles and bones should be exercised to maintain strength. Also, bone fractures that are exposed to permissible weight bearing stress often heal more predictably and more rapidly than fractures that are not stressed at all. Improved healing based on application of appropriate stress is also believed to be true for connective tissue, such as ligaments and certain cartilage.
Suitable stress can be applied to the tissue by the performance of selected exercises. For example, isometric exercise generally involves the exertion of force against a relatively immovable object, which allows no motion of the limb. To perform isometric exercises, a restraining device can be used that has a substantially unchanging position for the duration of a particular exercise routine. Isotonic exercises involve exertion against the same weight or resistance through a range of motion. Isokinetic exercise is designed to mimic exertions that take place on a playing field or the like. When performing isokinetic exercises in a simulated environment, a machine is used to provide resistance in direct proportion to the exertion of the exerciser.
Isometric exercises are particularly useful with painful injuries to lower the risk of further injury. Also, because isometric exercises are performed in a static position, they allow very position specific therapy. For example, to climb stairs, a person needs more strength at an approximate 60° knee bend, when combined with the hip and ankle joints. Therefore, the isometric exercises can be designed to focus on the strengthening of a joint at optimum angles where additional strength is needed. If performed in a controlled manner, isometric exercises can be performed earlier in the recuperation period to speed recovery. As the patient's recovery progresses, isotonic exercises or other exercises can be used to reestablish a desired strength through a range of motion about a joint. As recovery progresses eventually the patient is able to perform a full range of exercises.
A difficulty with application of stress to an injured joint include a risk of inappropriately timed or excessive stress. This can impair healing and/or further injure the damaged tissues. Thus, exercises need to be carefully planned to provide appropriate amounts of stress. Also, the performance of the exercises should be monitored closely to reduce the risk of injury. Moreover, the need to carefully plan and closely monitor the exercises provides a cost and motivation barrier to accessing desirable amounts of exercise.